Enhanced oxalate transport in nucleated red blood cells.
OBJECTIVE
This study was aimed to determine the presence of oxalate exchange/binding protein in the nucleated red blood cells (RBC).


METHODS
Intact RBC, nuclei, RBC membrane, nuclear membrane and histones were isolated and 14C-oxalate exchange/binding was studied.


RESULTS
The rate of oxalate anion exchange by nucleated erythrocytes was found to be higher (K = 1.24/min) than that of human RBC (K = 0.51/min) but less than that of nuclei (K = 1.55/min). Oxalate flux rate was pH- and temperature-dependent. Oxalate exchange was reduced by 35% for both chicken RBC and nuclei in presence of sulfate, bicarbonate, phosphate and succinate. Both plasma membrane and nuclear membrane showed maximal oxalate binding activity at pH 7.4, while in the nuclear basic protein fraction it was at pH 4.5. 4,4'-Diisothiocyanostilbene-2,2'-disulfonate, an anion transport inhibitor, inhibited the oxalate exchange and binding activity in both erythrocytes as well as nucleus.


CONCLUSIONS
Nucleated RBC can be useful model system for studying the interaction of oxalate with nuclear components.
Selvam
R
R
Department of Medical Biochemistry, Dr. A.L. Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani, India.
Devi
V S
VS
D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D001692:Biological Transport; D002250:Carbon Radioisotopes; D002645:Chickens; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009685:Nuclear Envelope / Q000378:metabolism; D010070:Oxalates / Q000097:blood*; D010710:Phosphates / Q000494:pharmacology; D019802:Succinic Acid / Q000494:pharmacology; D013431:Sulfates / Q000494:pharmacology
D001639:Bicarbonates; D002250:Carbon Radioisotopes; D010070:Oxalates; D010710:Phosphates; D013431:Sulfates; D019802:Succinic Acid